Cabling with Internal and External CSU/DSUs

Cabling with Internal and External CSU/DSUs

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When you're using internal CSU/DSUs, the cable from the telco plugs into the serial interface of the router. With external CSU/DSUs, the cable plugs into the CSU/DSU. An external CSU/DSU connects to the router using another short cable, typically less than 50 feet long. These short cables have numerous options for their connectors, so this book won't get into details about these cables. However, when you order the router and the CSU/DSU, the product documentation will suggest cables, which you'll typically buy from the router vendor when you order the router.